Mattresses Having a Matrix Core of Foam Elements

ABSTRACT

A mattress is constructed of a core comprising a matrix of foam pieces that are bonded together. The core has a thickness in the range from about 1.5 inches to about 10 inches, and more particularly from about 3 inches to about 8 inches, a density of about 4 pounds to 8 pounds per cubic foot, and an IFD of about 28 to 65. The core has a top surface and a bottom surface. A base layer is coupled to the bottom surface of the core, and a cushion layer is coupled to the top surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional ApplicationSerial No. 61/554,413, filed Nov. 1, 2011, titled “Mattresses Having aMatrix Core of Foam Elements,” the entire contents of which are herebyincorporated by reference.

BACKGROUND OF THE INVENTION

This invention relates generally to the field of mattresses. Inparticular, the invention relates to mattress that utilize a core madeup of a matrix of foam elements.

Spring mattresses have been in use for over 100 years. Existing springmattresses use a variety of spring types to form their inner core.Perhaps the most common is the traditional wire spring assembly having aset of interconnected wire spring coils.

As manufacturing processes have improved, it is becoming more common touse other types of cores, including cores made of a single material,such as a core constructed from a solid piece of latex or polyurethane.

This invention relates to mattress using other types of cores. Suchcores take advantage of reclaimed or repurposed materials that wouldotherwise be discarded (e.g., as being unusable cut sizes or foamdensities after foam manufacturing runs).

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the invention provides a mattress that is constructedof a core comprising a matrix of foam pieces that are bonded together.The core has a thickness in the range from about 1.5 inches to about 10inches, and more particularly from about 3 inches to about 8 inches, adensity of about 4 pounds to 8 pounds per cubic foot, and an IndentationForce Deflection (IFD) of about 28 to 65. For convenience of discussion,the core may have a top surface and a bottom surface. A base layer iscoupled to the bottom surface of the core, and a cushion layer iscoupled to the top surface. In this way, remnant foam pieces that mayotherwise be discarded may be used to form a relatively dense mattresscore. For example, the foam pieces may comprise polyurethane, urethaneand the like.

In one aspect, the cushion layer comprises a visco-elastic material. Inanother aspect, a top layer is positioned above the cushion layer. Aflame or fire retardant sock (referred to as an FR sock) may also beprovided to enclose the completed mattress. Per regulations, thisprovides a covering for the mattress that meets an open flame standard.Alternatively, a flame retardant or resistant fiber layer may beprovided below quilting if desired. Further, a cover, also known as aticking, is typically employed to envelope the core, the base layer andthe cushion layer. The cover may also be either quilted (to form apillow top mattress), a plush quilted or non-quilted.

In a further embodiment, the invention provides an exemplary method forconstructing a mattress. In one step of the process, a loaf is formed bycombining a plurality of foam pieces and a bonding material into agenerally rectangular mold and applying heat. In this way, the resultingloaf has a top, a bottom and four sides. To form a core, a rectangularsection is cut from the loaf, and will typically have a thickness in therange from about 3 inches to about 8 inches. The resulting core may havea density in the range from about 4 pounds to about 8 pounds and an IFDin the range from about 28 to about 65. A base layer is attached to abottom surface of the core, and a cushion layer is attached to a topsurface of the core. Typically, a cover is placed about the mattress.

The mattresses described herein may be useful as mattresses forconventional beds, but they may also be useful for mattresses used witha sleeper sofa, camper beds, yacht beds, cruise-ships beds, play mats,gym mats, camping pads, nap pads, or any other potential use where acore with a padded surface may be desirable. The term “mattress” as usedherein is intended to encompass these and other appropriate uses.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a schematic cross sectional side view of oneembodiment of a mattress according to the invention.

FIG. 2 is an exploded schematic top perspective view of the mattress ofFIG. 1, showing various component layers, not necessarily to scale.

FIG. 3 illustrates a schematic cross sectional side view of anotherembodiment of a mattress according to the invention.

FIG. 4 illustrates a mattress according to one of the embodimentsdescribed herein, with a layer of ticking disposed over the foam core,base layer, and cushion layer.

FIG. 5 illustrates a cross-sectional view of another mattress accordingto one embodiment of the invention.

FIG. 6 illustrates the mattress of FIG. 5, having various componentlayers rolled back at one corner.

FIGS. 7-12 illustrate testing results for certain mattresses accordingto various embodiments of this invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the invention provide various mattress that utilize acore made up of a matrix of foam pieces or elements that are bondedtogether. The core is relatively dense, significantly more dense thantraditional polyurethane cores. This increased density provides astronger and more durable core while providing a more comfortable feel.Another significant advantage of using a matrix of foam pieces is thatsuch foam pieces may be repurposed or otherwise reclaimed materials. Notonly is this friendly to the environment, it also significantly reducesthe cost of the mattress.

Hence, the core may be constructed to have a high density along with adurable construction to provide increased life. This matrix of foampieces is also firm and is constructed of a variety of small urethane orother foam pieces (typically re-purposed foam pieces, for example newfoam that cannot be cut into other pieces of the desired size orsections of foam that are not the desired density for other purposes,allowing the foam to be re-purposed in a new fashion) that are joinedtogether using an adhesive, heat and steam that tend to increase thedensity. One particularly useful method for constructing cores usingsuch a process is described hereinafter.

Further, the core may be constructed to be relatively dense, has an IFDin the range from about 28 to about 65 and is relatively inexpensive.Other types of materials that may be used include polystyrene materials,polyurethane, densified fibers and the like. The IFD, or IndentationForce Deflection, refers to the hardness or softness of the foam. Forexample, the higher the IFD, the firmer the foam. IFD is defined as theamount of force, in pounds, required to indent a fifty square inch,round indentor foot into a predefined foam specimen a certain percentageof the specimen's total thickness. IFD is specified as a number ofpounds at a specific deflection percentage on a specific height foamsample, e.g., 25 pounds applied to 50 square inches at a 25% deflectionon a four inch thick piece.

A wide variety of optional layers may be coupled to the top and/orbottom surface of the core. For example, another dense foam material maybe coupled to the bottom of the core. A variety of layers may be placedon top of the core, including additional padding layers, ticking, foam,a quilted layer, or the like.

In some embodiments, one or more cushion layers may be placed above thecore. These may be constructed of a material such as a polyurethane orlatex foam, a visco-elastic or memory foam material, or the like. Theseadditional padding layers may be used to provide the mattress withadditional comfort and may be used alone or in various combinations. Oneor both sides of these cushion layers may be surface modified usingvarious machining processes. Examples of surface modifications includeconvoluted, contoured, and the like. Other materials that may be usedinclude fiber padding materials. Further, mattresses of the inventionmay include a layer of ticking that is a piece of fabric or quiltingthat envelopes the mattress as is known in the art. The ticking maycomprise essentially any type of fabric or covering and may be sewn toform it around the core and other padding layers.

Referring now to FIGS. 1 and 2, one embodiment of a mattress 10 will bedescribed. Mattress 10 includes a core 12 that is constructed of aplurality of foam pieces that are bonded together to form a matrix. Core12 typically has a thickness in the range from about 3 inches to about 8inches, but may range anywhere from 1.5 inches to about 10 inches. Onespecific embodiment has a core that is about 4.5 inches to about 7.5inches. In a particular embodiment, the core thickness may range fromabout 3 inches to about 5 inches, and may specifically be about 4.5inches. In an alternate embodiment, the core thickness may range fromabout 4 inches to about 6 inches, and may specifically be about 5.5inches. In a further embodiment, the core thickness may range from about6 inches to about 8 inches, and may specifically be about 7.5 inches.The core should be thick enough to provide appropriate support forsleeping and/or otherwise supporting one or more people, but should bethin enough that the mattress does not become unwieldy to transport orso large that sheets are difficult to secure in place about themattress.

The core may also have a density of about 4 pounds to 8 pounds per cubicfoot, and an IFD of about 28 to 65. The density may be varied based uponthe size and number of foam pieces used, as well as the type of binderused. Core 12 has a top surface 14 and a bottom surface 16. One exampleshowing how smaller foam pieces may be bonded to one another in order toform core 12 is shown in FIG. 5, and such methods of manufacture aredescribed further below.

Coupled to bottom surface 16 may be a base layer 18. The two may becoupled together by glue, a bonding material or the like. Base layer 18will typically be a piece of foam that is less dense than core 12 andmay have a thickness in the range from about 0.25 inch to about 4inches. In a particular embodiment, the base layer thickness may rangefrom about 0.5 to about 2 inches, and may specifically be about oneinch. The density may be in the range from about 1 pound per cubic footto about 2 pounds per cubic foot, with an IFD of about 28 to about 70.Base layer 18 in some cases serves to help hold together the foam piecesin the matrix, thus increasing the life of the mattress.

Secured to top surface 16 is a cushion layer 20. One exemplary materialthat may be used to construct cushion layer is a visco-elastic foam, gelviscoelastic foam, air ventilated viscofoam with enhanced breathingproperties, memory foam, down feathers, synthetic down alternative,latex, any combination thereof, or any other appropriate cushion-likesurface that adds comfort and padding to the mattress. The cushion layer20 may be formed as a combination of one or more comfort layers. Thedensity of this cushion layer may be in the range from about 2 poundsper cubic foot to about 6 pounds per cubic foot. In a particularembodiment, the density may range from about 2 pounds per cubic foot toabout 5 pounds per cubic foot, and may specifically be about 3 poundsper cubic foot or about 3.5 pounds per cubic foot. The height of thecushion layer may be about 1 inch to about 6 inches, more specificallyfrom about 1 inch to about 5 inches, and more specifically, from about 2inches to about 4.5 inches, and even more particularly, about 4.5inches. The cushion layer may have an IFD rating of about 6 to about 18.FIGS. 1 and 2 show a single layer of visco-elastic foam, and FIGS. 5 and6 show other embodiments having multiple layers of visco-elastic foam orother cushion-like material. Cushion layer may also be a combination ofair insulated viscofoam with enhanced ventilating properties so that itbreathes more and keeps the sleeper cooler.

The various layers may have different densities and or IFD ratings. Asshown in FIG. 5, in a particular embodiment with the cushion layerformed of two layers, one layer 20 may be a visco-elastic memory foamand another layer 24 may be a second visco-elastic memory foam layer ora gel visco-elastic memory foam layer. The first lower visco-elasticmemory foam layer may be about 3 to about 3.5 inches thick and may havea density of about 3 to about 3.5 pounds per cubic foot. The secondupper visco-elastic memory foam layer or gel visco-elastic memory foamlayer may be about 1 to about 1.5 inches thick. Providing two layers inthe cushion layer can add additional comfort to the mattress.

A flame or fire retardant sock (referred to as an FR sock) may also beprovided to enclose the completed mattress. Per regulations, thisprovides a covering for the mattress that meets an open flame standard.Alternatively, a flame retardant or resistant fiber layer may beprovided below quilting if desired. A cover ticking 22 may be used toenvelop the mattress. Ticking 22 comprises a fabric that is securedabout the various layers. FIG. 4 shows a mattress that has beenenveloped by a layer of ticking 22.

As shown in FIG. 3, various other layers may be provided on mattress 10to change the look and feel of the mattress. These could be includedbeneath the ticking 22, such as with layer 24, or above ticking 22, suchas in the case of an independent topper 26. These additional layers maybe surface modified, such as convoluted. Examples of materials that maybe used for the additional layers include latex, gel materials, fibrousspacer materials, that may optionally include a gel material, and thelike. Also, various backing materials and fire resistant layers ormaterials may be used as well.

To construct core 12, multiple foam pieces are used. These may be ofvarious shapes and sizes. Merely by way of example, these foam piecesmay have a size in the range from about 0.25 inch by about 0.25 inch byabout 0.25 inch to about 3 inches by about 3 inches by about 1 inch.Often, these may be pieces or remnants from other applications that canbe repurposed rather than discarded. This often leads to the varioussizes of pieces that may be used. For example, various pieces of remnantfoams may be collected, then shredded down to smaller pieces. Theindividual pieces then need to be coated with a binder or resin, such asa polyurethane binder. This may be performed by feeding the pieces intoa large container where the foam pieces are sprayed or otherwise mixedwith the binder.

After the pieces are coated with the binder, they are fed into a mold.To facilitate the construction of a core that is to be used for amattress, the foam pieces are placed within a rectangular mold. Thismold may have various sizes depending on the desired size of themattress. Merely by way of example, the mold may have a size in therange from about 60 inches by about 80 inches, with a height of about 3feet to 4 feet. For larger mattresses, multiple cores may be bondedtogether. For example, two cores that are the size of a twin mattresscould be bonded together at their sides to obtain the size and shape ofa king sized mattress. A compression member that may be driven by apiston is used to compress the foam pieces to the desired density withinthe mold. Also, it will be appreciated that the density of theindividual pieces will also contribute to the resulting density. Themold is then subjected to steam to cure the binder and allowed to cool.The resulting loaf is removed from the mold and has a rectangular shape.This loaf may be sliced into multiple layers in order to form separatecores. Additional timing to size may also be performed.

Mattresses made according to the various embodiments described hereinwere subjected to various tests in order to determine the firmness andfatigue resistance of the mattresses. The tests conducted are generalprotocol in the bedding industry. First, the firmness of the mattress isscanned and measured prior to any fatigue test. For this test, a 15″circular plate is depressed into the bed in about nine locations, andthe pounds of pressure required for the plate to press 75% into themattress is measured. The plate then moves to 25% depression, whichgives the IFD (indentation force deflection). Next, a rollator (which isa 3 foot, six-sided, 230 pounds log) rolls back and forth across centerof mattress for about 10,000 cycles. The mattress rests 24 hours and isscanned, which electronically measures any loss/gain of height. The IFDtest is conducted again as well. Additional cycles of 25,000 cycles,50,000 cycles, 75,000 cycles and 100,000 cycles are run, repeating therest, scan & IFD test. It is believed that about 100,000 cyclesapproximates 10 years of use.

Exemplary results for selected tests are outlined in the attachedfigures. FIG. 7 shows testing results from tests conducted on a mattresshaving the following parameters. FIG. 8 illustrates percentage changesin firmness of the mattress after such tests.

Mattress type: Green Choice Elegant 11″ (Core: 6.5 inches+1 inch supportfoam layer as base layer; cushion layer: 3.5 inches (1.5 inch airinsulated viscofoam with ventilating properties +2 inches of regularviscofoam above core)

FIG. 9 shows exemplary results for selected tests conducted on amattress having the following parameters. FIG. 10 illustrates percentagechanges in firmness of the mattress after such tests.

Mattress type: Green Choice Bliss 10″ (Core: 4.5″ ES Core+1″ supportfoam; cushion layer: 3.5″ 3 lbs ViscoElas Memory Foam+1″ ViscoElasMemory Foam topper)

FIG. 11 shows exemplary results for selected tests conducted on amattress having the following parameters. FIG. 12 illustrates percentagechanges in firmness of the mattress after such tests.

Mattress type: Green Choice Relaxation 11″ (Core: 5.5″ ES Core+1″support foam; cushion layer: 3″ 3 lbs ViscoElas Memory Foam+1.5″ GelViscoElas Memory Foam topper)

The invention has now been described in detail for purposes of clarityand understanding. However, it will be appreciated that certain changesand modifications may be practiced within the scope of the appendedclaims.

What is claimed is:
 1. A mattress comprising: a core comprising a matrixof foam pieces that are bonded together, wherein the core has athickness in the range from about 1.5 inches to about 10 inches, adensity of about 4 pounds to 8 pounds, and an IFD of about 28 to 65, thecore having a top surface and a bottom surface; and a cushion layercoupled to the top surface.
 2. The mattress of claim 1, wherein the corethickness ranges from about 3 inches to about 8 inches'.
 3. The mattressas in claim 1, wherein the cushion layer comprises a visco-elasticmaterial.
 4. The mattress as in claim 1, further comprising a top layerpositioned above the cushion layer.
 5. The mattress as in claim 1,further comprising a cover enveloping the core, the base layer and thecushion layer.
 6. The mattress as in claim 5, wherein the cover isquilted.
 7. The mattress as in claim 5, wherein the cover has flameretardant or flare resistant features.
 8. The mattress as in claim 1,wherein the foam pieces comprise polyurethane, urethane, or acombination thereof
 9. The mattress as in claim 1, further comprising abase layer coupled to the bottom surface of the core.
 10. The mattressas in claim 9, wherein the base layer comprises a support foam layer.11. A method for constructing a mattress, comprising: forming a loaf bycombining a plurality of foam pieces and a bonding material into agenerally rectangular mold and applying heat, wherein the resulting loafhas a top, a bottom and four sides; cutting a rectangular section fromthe loaf to form a core, wherein the rectangular section has a thicknessin the range from about 1.5 inches to about 10 inches; attaching a baselayer to a bottom surface of the core; attaching a cushion layer to atop surface of the core.
 12. A method as in claim 11, further comprisingplacing a cover about the mattress.
 13. A method as in claim 11, whereinthe core has a density in the range from about 4 pounds to about 8pounds and an IFD in the range from about 28 to about
 65. 14. A methodas in claim 11, wherein the bonding material comprises a polyurethanebinder.
 15. A method as in claim 11, wherein the plurality of foampieces comprise repurposed pieces or remnants from other applications orfrom foam manufacturing runs that are otherwise unusable.